Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
May contain nuts.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                                                         

Backwards Bow and Arrow

 Reverse bow and front launch arrow solves an age old problem
  (+7, -1)
(+7, -1) 		  [vote for,
against]

Anyone who has seen a high speed video of an arrow in flight (Myth Busters) knows that it wobbles. This is a result of the launching force being applied to the rear end of the arrow. The force of the string accelerating the arrow from the back end causes the shaft to deflect which results in an oscillation that tends to cause the arrow to wander slightly (my theory). The solution to the problem is to turn thing around and accelerate the arrow from the pointy end. In this case a small notch will be made just behind the tip to engage the string. A secondary guide string could be used at the traditional end to align the arrow and draw the bow.
—bingalls01, Aug 23 2006

Swiss Arrow http://en.wikipedia.org/wiki/Swiss_arrow
Arrow with a notch in the shaft [Zimmy, Aug 23 2006]

"Rest Energy" http://www.eyestorm...e.asp?article_id=38
Artist Marina Abramovich's use of a bow and arrow to create a most excellent art work. Scroll down the page and it's near the bottom [xenzag, Aug 26 2006]

Please log in.
If you're not logged in, you can see what this page looks like, but you will not be able to add anything.
Short name, e.g., Bob's Coffee
Destination URL. E.g., https://www.coffee.com/
Description (displayed with the short name and URL.)






       I think this age old problem was probably solved with the rifle. But in any case, why stop at two strings? Use a dozen of them, with notches on the arrow to match. You'd have a bow that looks like a harp.
—ldischler, Aug 23 2006
   

       Interesting.   

       The string will be exiting the slot at an angle when it releases. Would that cause a sideways deflection at the tip?   

       The arrow will be acclerated by a force that is not in line with the center of the arrow (unless the notch is really deep). Would that adversely affect the flight?   

       The fletching would most likely contact the string as it goes by. Would that set up any sort of oscillation in the arrow? (Probably less interference than what happens in the conventional design)   

       Would the bow be backward or would the bulk of the arrow be behind the archer when in the drawn position?
—half, Aug 23 2006
   

       I would think that if this worked, someone would have used the arrow tip to accelerate the arrow in a crossbow design.
I think a mechanical rotating arrow tip holder (U-shaped?) could be designed to turn and avoid the fletching.
—Zimmy, Aug 23 2006
   

       -The notch would be shallow and annular. -11 strings is the theoretical maximum possible. -Another benefit is the fletching could be smaller or even eliminated due to additional dynamic stability. -The arrow would remain in front of the archer.
—bingalls01, Aug 23 2006
   

       //11 strings is the theoretical maximum possible//
Is that a string theory joke?
—ldischler, Aug 23 2006
   

       There are drop away arrow rests to address the fletching issue for conventional bows I believe. I'm not an archer, so am hesitant to suggest such potential solutions to my own questions.   

       The shallow notch then would have the effect of accelerating the arrow with a force applied off center. I wonder if it would be enough to make the arrow fly in some direction other than exactly in line with the string's path.   

       So, the bow is backward then. The bow is held in the hand and the string is drawn toward the bow. That sounds awkward the way I'm envisioning it. Would the bow not try to spin in your hand as you draw the string back?   

       Maybe I just need to see an illustration.
—half, Aug 23 2006
   

       Put a notch in the usual spot, just extend it past the center of balance of the arrow. :)
—GutPunchLullabies, Aug 23 2006
   

       Interesting idea, therefore bun. It would be intersting to see how the bow flexes in this configuration - I suspect it would lead to a more complex compression arrangement than the standard system. You're trying to put the arms of the bow into something much closer to pure compression, as opposed to soemthing much more like standard deflection.
—moomintroll, Aug 23 2006
   

       I can't find any info about an atlatl dart being "front flung". I would think it's been tried over the estimated 40,000 years of use, though.   

       + anyway, A 28" average arrow shaft would let you stare almost straight down the shaft when the bow is drawn.
—Zimmy, Aug 23 2006
   

       Can't help but think that either Mythbusters didn't do their research properly, or that you are misinterpreting it. Arrows were phenomenally successful weapons, and extremely accurate, and I can't help but think that if they wobble, it hardly matters very much.
—DrCurry, Aug 23 2006
   

       I've seen the video, there is a distinct oscillation about the center of the shaft and slight orbital motion of the tip. Another advantage of this approach is the shaft does not have to be nearly as rigid. I believe plastic with molded in fletching like a cheap hand dart would work.
—bingalls01, Aug 23 2006
   

       I think this used to be called the "Archer's Paradox". They had to get arrows matched to their bows, and practice a lot, but they were very accurate.
—baconbrain, Aug 23 2006
   

       [DrCurry], They were trying to "robin hood" an arrow. The oscillations were thought to be the cause of it being impossible to split the enitre shaft of another arrow.
—Zimmy, Aug 23 2006
   

       Arrows do oscillate in flight but the do so around their center of gravity and so this oscillation does not impact accuracy in fact it may actually increase it(as rifling does for Bullets) the tip and tail of the arrow do not oscillate just the center of the shaft so overall flight path is uneffected.   

       The whole point of launching an Arrow from the back is that the force can be centered on the shaft which is not possible in this scenario(except if the Notch extended to tip of arrow) any side loading will throw arrow off course, also interaction of the fletches with the string will be a real issue.   

       [zimmy] as far as i know the reason they could not robinhood the arrows had to do with the grain of the wood in the shaft interacting with the head of the arrow(deflecting it to the side due to friction and grain pattern), they were able to simulate the movie effect using bamboo(which is hollow) the tip of the arrow was not deflected.
—jhomrighaus, Aug 23 2006
   

       [jhom], you're right. I had forgotten that.
—Zimmy, Aug 23 2006
   

       I don't think that the fletching coming into contact with the string would have very much effect. Arrow fletching hits the frame of the bow on nearly all conventional bows with little effect. As said before, arrows can be extreemely accurate, and only in the last few years have devices been made to keep the fletching from touching anything. And even if the force was applied to the arrow off-center, as long as the deviation was consistent, accuracy would not be affected. A golfer with a consistent slice can adjust for it and make as accurate of a shot as a golfer without one. (I'm not a golfer, but I think it works that way.)
—Hunter79764, Aug 23 2006
   

       Accepting for the moment that all of that is true, I still can't visualize the bow or the ability to pull the string back while holding the bow steady.   

       Drawing back a bow conventionally takes the hands apart from one another creating a fairly stable arrangment. But, pulling the string back toward the bow would bring the hands closer together causing bad things to happen to the stability of the whole system.   

       Or am I totally missing the boat here? (Would not be the first time).
—half, Aug 24 2006
   

       [half], I thought about the arrangement for quite a long time.
At first, I thought it would be impossible to maintain the arrow parallel to the bow & string and also perpendicular to the midpoint of the string. (I wish I knew how to describe that better.)		   

       The way I am imagining the Backwards Bow is a backwards D shape that points away from you w/ the string forming the straight vertical. When the bow is drawn w/ arrow, I imagine some thing closer to an I shape. Initially I thought there would have to be an arrow guide, but now I'm not sure.
If you were holding the Backwards bow properly & drew back the arrow right below your eye, the guide might not be necessary.		   

       I also have imagined a rack of arrows of to the right (as I am right handed) where you shoot, grab an arrow, hook the string w/ the arrowhead, draw, fire. It would be so much faster than the standard arrangement.   

       I think your left & right hands would still end up in about the same position as they would conventionally when the bow was drawn, if I understand correctly.
—Zimmy, Aug 24 2006
   

       I was imagining that the backwards bow worked something like this:
The user pulls back like hell and then lets go. The bow clobbers the enemy round the head, and the user is left holding the arrow.
—Ling, Aug 24 2006
   

       I'm wondering - is the arrow extreemely accurate or is the archer extremely accurate? Does skill overcome uncontrolled variables?
—bingalls01, Aug 24 2006
   

       Pulling from the front is bad for accuracy. (Oh, and the tool weilder can't be any more accurate than the repeatiblity of the tool being used.)   

       Once the string's done pulling, you need to have it get out of the way really fast, (how?) or else, the arrow's shaft will be passing by it and will be affected by the local "wind", just on one side (where the string is).   

       Oh, and pulled objects are much more likely to go end-over end. Pushing it helps keep it more stable.
—sophocles, Aug 24 2006
   

       On first glance, this is a contender for health:suicide.
—Cuit_au_Four, Aug 26 2006
   

       No, It's Not! Make a paper airplane & throw it holding on from the very back. Now throw it holding it from the front. Best of 10?
—Zimmy, Aug 26 2006
   

       The atlatl version of this is very interesting to me. It would not be hard at all to devise an atlatl that hooked at the spearhead. The leverage advantage of an atlatl should be the same regardless of where it interfaces with the spear.
—bungston, Aug 26 2006
   

       [bungston], I ran across some references, that I probably won't be able to find now, that studied whether the flexure of the dart (being back flung) had anything to do with the speed or accuracy of an atlatl flung dart.
The study seemed to indicate that the flexure had nothing to do with anything - I hope unlike my anno's.
—Zimmy, Aug 26 2006
   

       I still don't understand how this is physically possible. You may only be pulling with a 60 pound force, but you'd probably have well over 140 ft-lb torque trying to rotate this thing in your hand.
—Laimak, Aug 27 2006
   


 

back: main index
business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle